python_pinger.git

1) #!/usr/bin/python3
2) #
3) # Since this is meant to be run as a daemon, do not use #!/usr/bin/env python3,
4) # because the process name would then be python3, not based on __FILE__.
5) #
6) # [filename] -d 3 192.168.1.1 192.168.1.12 &
7) # disown [jobid]
8) import os
9) import sys
10) import subprocess
11) import time
12) from argparse import ArgumentParser
13) import threading
14) import queue

15) import signal

16) 

17) pinger_lock = threading.Lock()
18) 

19) 

20) def log_exit(sig, frame):
21)     _print_queue.put([f'{time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())} '
22)                       f'PID={os.getpid()} signal={signal.Signals(sig).name} Exiting.'])

23)     _print_queue.join()
24)     sys.exit(0)
25) 
26) 

27) def pinger(host):
28)     """Executes one ping, prints if there was a change, exits thread."""
29)     now = time.localtime()
30)     success = ping(host)

31)     with pinger_lock:
32)         # Access to _results needs to be serialized
33)         need_update = success != _results[host]
34)         if need_update:
35)             _results[host] = success
36)     if need_update:

37)         status = "UP" if success else "DOWN"
38)         _print_queue.put([f'{time.strftime("%Y-%m-%d %H:%M:%S", now)} {host} {status}'])
39) 
40) 
41) def ping(host):
42)     """Returns True if host (str) responds to a ping request."""
43)     return subprocess.call([*_ping_cmd, host], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL) == 0
44) 
45) 
46) def print_manager():
47)     """ The only thread allowed to write output. """
48)     while True:
49)         job = _print_queue.get()
50)         for line in job:
51)             log(line)
52)         _print_queue.task_done()
53) 
54) 
55) def log(*args, **kwargs):
56)     """Opens the logfile, writes the log, and closes the logfile."""
57)     # I don't leave the log file open for writing because another process needs access too.
58)     with open(_logname, 'a') as fp:
59)         return print(*args, **kwargs, file=fp)
60) 
61) 
62) if __name__ == '__main__':
63)     parser = ArgumentParser(description="Repeatedly ping sites. Ex: %(prog)s -d 3 192.168.1.1 192.168.1.12")

64)     parser.add_argument('-d', '--delay', type=float, default=3.0, help='Delay between pings')

65)     parser.add_argument('addresses', nargs='+', help='Addresses to ping')
66)     parser_args = parser.parse_args()
67) 
68)     _results = dict()
69)     for addr in parser_args.addresses:
70)         _results[addr] = None
71)     delay = parser_args.delay
72)     _logname = os.path.join(os.path.expanduser('~'), 'log', os.path.basename(sys.argv[0]).replace('py', 'txt'))
73) 
74)     # Choose the ping parameters appropriate for the platform
75)     if sys.platform == 'cygwin' or sys.platform == 'win32':
76)         _ping_cmd = ('ping', '-n', '1', '-w', '2000')
77)     else:
78)         _ping_cmd = ('ping', '-c', '1', '-W', '2', '-q')
79) 
80)     _print_queue = queue.Queue()
81)     t = threading.Thread(target=print_manager, daemon=True)
82)     t.start()
83)     del t
84) 

85)     signal.signal(signal.SIGINT, log_exit)
86)     signal.signal(signal.SIGTERM, log_exit)
87) 

88)     _print_queue.put([f'{time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())}'

89)         f' PID={os.getpid()} repeat={delay}s addresses={",".join(parser_args.addresses)} Starting'])